Fact 1 (Kronecker substitution [1]}) 
Let \(P(x_1, x_2, \ldots , x_n)\)  be a multivariate polynomial of degree \(d\) . We replace
every occurence of variable \(x_i\)  by \(x^{d^i}\) . This yields an unique univariate polynomial
\(Q(x)\)  of degree at most \(d^{O(n)}\)  such that \(P\)  can be efficiently recovered from the knowledge
of coefficients of \(Q\) . When the number of variables is a constant, the degree of the multivariate
polynomial and the univariate polynomial are polynomially related.

